1. Field of the Invention
The present invention relates to a method of manufacturing TAB (tape automated bonding) tapes and to a laminated body for use in manufacturing the TAB tapes, and more particularly it relates to such a method which can be carried out at a low cost and efficiently and also allows existing conventional equipments for producing one strip of TAB tape to be used for manufacturing plural separate strips of desired TAB tape at the same time, by providing an adhesive layer and a copper foil over the entire surface of a base film except both the edge portions thereof, the base film having such a width that two or more TAB tapes having a desired width are obtainable, and also relates to such a laminated body for manufacturing therefrom TAB tapes, which is an intermediate product obtained in the course of manufacture of the TAB tapes.
2. Prior Art
In a case where TAB tapes having a width of, for instance, 35 mm are attempted to be manufactured, they will generally be manufactured from a base film having a width of 70 mm and other necessary materials to obtain a wide TAB tape and then slitting the thus-obtained wide TAB tape in the longitudinal direction into two equal parts thus obtaining two separate strips of 35 mm-wide TAB tape. This is a so-called method for manufacturing a binary TAB tape.
FIG. 2 shows an example of a conventional method for manufacturing two separate strips of TAB tape at the same time by using said so-called method. FIG. 2 is a schematic cross sectional view showing the steps which are comprised in the conventional method.
In the Figure, reference numeral 1 is a base film which is wide, 2 an adhesive layer, 3 a protection film, 4 a sprocket hole, 5 a copper foil, 6 a photoresist, 7 a wide (twice the width of a desired tape) TAB tape and 8 a desired TAB tape.
In FIG. 2, the adhesive layer 2 having the protection film 3 provided thereon is laminated on the base film 1 as a substrate (FIG. 2(b)), and holes such as sprocket holes 4, 4' and device holes 9 are then drilled in the central portion as well as in both the edge portions 10, 10 of the base film 1 (FIG. 2(c) and FIG. 4). After the protection film 3 is peeled off the adhesive layer 2, the copper foil 5 is adhered to the adhesive layer 2 (FIG. 2(d)). The photoresist 6 is applied to this copper foil 5, exposed and then developed thereon (FIG. 2(e)), after which a backing agent is applied to the reverse surface of the base film 1 (not shown herein) and then the photoresist-developed copper foil 5 is etched to form wiring patterns (FIG. 2(f)). The thus manufactured wide TAB tape 7 for producing therefrom two separate strips of TAB tape at the same time, the wide TAB tape consisting of two strips of TAB tape originally connected to each other in parallel, is slit (divided) into two parts at the center in the longitudinal direction of the wide TAB tape thereby to obtain two separate strips of TAB tape 8 (FIG. 2(g)).
It should be noted that, generally prior to or after the step of slitting as described above, a solderresist ink is screen-printed on the wiring patterns and cured, after which the solderresist-cured wiring patterns are subjected to plating. In this case, it is optional whether or not the solderresist is printed on the wiring patterns before the plating.
In a conventional method for producing two separate strips of TAB tape at the same time as described above, as shown in FIGS. 2(a) to (d) and particularly FIG. 4, two strips of the protection film-covered adhesive layer or two strips of the copper foil are laminated on or adhered respectively to spaces 2', 2' (hatched portions) located at the right and left side portions of the regions between the sprocket holes 4 and 4' by using 2 roll-out devices for the lamination or adhesion set up respectively at said right and left side portions. Namely the lamination or adhesion is separately executed at the right and left side portions of the base film. For this reason, such 2 roll-out devices for lamination or adhesion are required, and the devices have to be controlled separately at the right and left side portions of the base film, thus causing the setting of the devices to be complicated. Further, because the 2 devices are utilized, there will often occur positional displacements of the adhesive layers or copper foils at both the side portions on the base film, respectively, whereby it is very often difficult to slit the resulting wide TAB tape into two separate TAB tapes. It should be noted that, FIG. 4 is a plan view showing areas on which the adhesive layers are separately laminated in the conventional method for manufacturing two separate strips of TAB tape at the same time, and in the figure, reference numeral 2' designates an area on which the adhesive layer is to be laminated, and 9 a device hole.
Before forming wiring patterns by etching the copper foils, a backing agent as an etching resist is applied to the reverse surface of the base film (the reverse side of the base film surface to which the copper foil is adhered) at each of the right and left side portions of the reverse just below the copper foil, but in this case, the backing agent trickles to the surface (to which the copper foil is adhered) on which wiring patterns are to be formed, through the sprocket holes in the central portion of the film, thereby to cause a short of the wiring.
Further, in the conventional method for producing two separate strips of TAB tape at the same time, the central portion of the base film on which the adhesive layer and copper foil are not laminated is naturally thinner than other portions thereof, and for this reason it is required that a conventional production line for producing two separate strips of TAB tape at the same time is necessarily provided with rollers to support the central portion of a base film upward so that the central portion does not sag.
On the other hand, in a case where one strip of TAB tape is produced from one base film and other necessary materials, namely, in case of so-called one-strip production, it is not necessary to support upward the central portion of the base film on which an adhesive layer and a copper foil are laminated since the central portion of the laminated base film is identical in thickness with its surrounding portions. In cases where there should be provided such rollers as to support the central portion, no problem will be raised when the laminated film is passed with its wiring pattern being faced upward, whereas inconveniences will be incurred since such rollers constitute an obstacle or bar to the wire pattern when the laminated film is passed with its wiring pattern being faced downward (The same is applicable to a case where the laminated film has wiring pattern respectively on both the faces thereof.). Thus, such rollers as to support upward the central portion are usually not provided on the one-strip producing line except the place where the laminated base film is passed with its wiring pattern being faced upward.
Accordingly, there have heretofore been needed separately an exclusive two-strip producing line requiring rollers to support the central portion of the laminated film and an exclusive one-strip producing line requiring no such rollers, this being uneconomical because one producing line cannot be commonly used as said one- and two-strip producing lines. More specifically, even if a 70 mm-wide base film is commonly used in each of the following cases, a conventional line for producing one strip of 70 mm-wide TAB tape is not applicable to production of two separate strips of 35 mm-wide TAB tape at the same time.
Namely, in this manner a conventional method for producing at least two separate strips of TAB tape at the same time is not efficient from the standpoint of equipment and operation employed because of being unable to use equipments for producing one strip of TAB tape.